---
cve: "CVE-2026-49114"
severity: "MEDIUM"
cvss: 6.8
epss: "0.2%"
vendor: "onnx"
kev: false
exploited: false
published: "2026-08-21 16:17:17"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T03:05:42+02:00"
---

# CVE-2026-49114

> 6.8 MEDIUM · 🧪 PoC

## Beschreibung

In ONNX before 1.21.0, the 'save_external_data' function builds the external-data file path from the model's external_data location field and opens it for writing without 'O_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim's write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.

## CVSS-Vektor

```
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- be2b5fde82d9c8874f3d19328bdfe3b6962dc67b (Commit)

## Referenzen

- <https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6>
- <https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json>
- <https://www.cve.org/CVERecord?id=CVE-2026-49114>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-49114) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_